Porth's Essentials of Pathophysiology, 4e

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Integumentary Function

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of any secondary infections. Secondary candidal or other skin manifestations discussed in this chapter may occur in the diaper area. It is important to differentiate between normal diaper dermatitis and more serious skin problems. Prickly Heat. Prickly heat (heat rash) results from constant maceration of the skin because of prolonged exposure to a warm, humid environment. Maceration leads to midepidermal obstruction and rupture of the sweat glands. Although commonly seen during infancy, prickly heat may occur at any age. The treatment includes removing excessive clothing, cooling the skin with warm water baths, drying the skin with powders, and avoiding hot, humid environments. Cradle Cap. Cradle cap is a greasy crust or scale for- mation on the scalp. It usually is attributed to infre- quent and inadequate washing of the scalp. Cradle cap is treated using mild shampoo and gentle combing to remove the scales. Sometimes oil can be left on the head for minutes to several hours, softening the scales before scrubbing. Other emulsifying ointments or creams may be helpful in difficult cases. The scalp may need to be rubbed firmly to remove the buildup of keratinized cells. Recalcitrant cases need to be seen by a health care pro- vider; serious or chronic forms of seborrheic dermatitis may exist. Pigmented andVascular Birthmarks Pigmented birthmarks represent abnormal migration or proliferation of melanocytes. For example, Mongolian spots are caused by selective pigmentation. They usu- ally occur on the buttocks or sacral area and are seen commonly in Asian and black persons. Nevi or moles are small, tan to brown, uniformly pigmented solid macules. Melanocytic nevi are formed initially from aggregates of melanocytes and keratinocytes along the dermal–epidermal border. Congenital melanocytic nevi are collections of melanocytes that are present at birth or develop within the first year of life. They present as macular, papular, or plaquelike pigmented lesions of various shades of brown, with a black or blue focus. The texture of the lesions varies and they may be with or without hair. They usually are found on the hands, shoulders, buttocks, entire arm, or trunk of the body. Some involve large areas of the body in garmentlike fashion. They usually grow proportionately with the child. Congenital melanocytic nevi are clinically sig- nificant because of their association with malignant melanoma. Vascular birthmarks are cutaneous anomalies of angiogenesis and vascular development. 69 Two types of vascular birthmarks commonly are seen in infants and small children: bright red, raised hemangiomas of infancy and flat, reddish-purple port-wine stains. Hemangiomas of infancy (formerly called strawberry hemangiomas ) are small, red lesions that are noticed shortly after birth. 69 Hemangiomas of infancy are gen- erally benign vascular tumors produced by prolifera-

tion of endothelial cells. They are seen in approximately 10% of children in the 1st year of life, with about 60% being located on the head and neck. 69 Although they can occur anywhere on the body, they can be life-threatening when they occur in the airway. Approximately 30% of these lesions are present at birth while the remainder develop within a few weeks after birth. 69 Hemangiomas of infancy typically undergo an early period of prolif- eration during which they enlarge, followed by a period of slow involution during which the growth is reversed until complete resolution occurs. Most hemangiomas of infancy disappear before 5 to 9 years of age with- out leaving an appreciable scar. A small percentage of hemangiomas develop complications. Ulceration, the most frequent complication, can be painful and carries the risk of infection, hemorrhage, and scarring. Some hemangiomas are located in anatomic regions associ- ated with other anomalies requiring careful monitoring and early intervention. Port-wine stains are pink or red patches that can occur anywhere on the body and are very noticeable (Fig. 46-25). They represent slow-growing capillary malformations that grow proportionately with the child and persist throughout life. 69 There is progres- sive dilation of the dermal capillaries, which initially is confined to the immediate epidermis, with gradual involvement of deeper dermal blood vessels, although the greater number is always in the upper dermis. Distribution of lesions on the face roughly corresponds to the sensory branches of the trigeminal nerve. Port- wine stains usually are confined to the skin, but may be associated with vascular malformations of the eye, resulting primarily in glaucoma, or leptomeningeal involvement, leading to cognitive disorders, seizures, and other neurologic deficits (Sturge-Weber syndrome). Cover-up cosmetics are useful in concealing the stains. Laser surgery has revolutionized the treatment of port- wine stains.

FIGURE 46-25. Port-wine stain on the face. Congenital malformation of blood vessels. Usually appears at birth. (From Goodheart HP. Goodheart’s Photoguide to Common Skin Disorders. Philadelphia, PA: Wolters Kluwer Health | Lippincott Williams &Wilkins; 2009:521.)